Wave translating apparatus



Dec. 28, 1948.

Filed July 27, 1945 WAVE TRANSLATING APPARATUS RING ATTORNEY Patented Dec. 28, 1948 :fumi-Tfno s rfATfE-s .PAT E-,Nfi' `,9122111 C212 WAAVE TRANSLATING APPARATUS DouglasH.l-Ring,. Red Bank N. ".I., assignor to ,BellTelephonLaboratories, Incorporated; New YorkfNf Y., a; corporation of vNewr `vYork .implication July. 27, 1945,:SerialNo.' 607,429

14 Claims. Y.1 This invention relates tomicrowave translating apparatus, and particularly to such. apparatus.` provided with .a capability -dor handling a relativelyv large Vamount:off-signaling power.

In the developmentfzof.,signaling systems vfor f microwavesv .having -awavelength; of the order 'of k onemeter or less, one critical need is'a satisfactory modulating device for handling the amount o'f signaling .power finvolved. 4Toibe attractive ironia circuit standpoint, such :device should em- .ibodya capability forhandlingfa preselected-maximum. amount of signalingI power. This requires .the .modulating device to pass a maximum amountoff'signa'ling current for: long-.and continuous periods of time without showing vcanydeleterious eiects.

.The :present invention. contemplates-microwave :translating:1apparatus1- embodying a'f modulating v-device off substantiallyincreasedcurrent .carry- -ing capability.

:The object'oiithe invention is to providemicron wave: translating apparatus including. modulating. elements capable. of: handling .arlarge amount of the'constricted sectionf-andaplural'ity-offleads is connectedlto therectier elements and extends across the Wave guideto expose equal lengths interiorly thereof-and yto terminate outside lthereof. -A source of biasing voltage is connected' via these leads to` therectifier V4elements. -A signal source is Vconnected incircuit-with -such fleads and biasing source. It has-been' foundiinprac- 'tice that the foregoing'microwave'translating apparatus embodies a'substantiallyincreased'capability for handling signal energy.

The`invention will be readily. understoodv from the following ldescription taken ,together with the accompanyingdrawing in which:

Fig.. 1 is .a schematic circuit .diagraln .of .a microwave translating '..apparatus .rincluding A.a specific embodiment. of. the. .invention and showing an elevational-view..of..a. circuitelementdn cross-section;

. Eig-Zis-a plan viewnof Eigt 1;

.2 AFig. 3 is. an. enlarged view.of.a circuit element ofVF-ig. 1; and

"Fig-.4 isa sectional- View. taken along the'line `.4-'.4 iniFig. 3.

Herein,..the.term microwave"denotes a wave v.having-a' length less .than onemeter, andas. short as one. centimeter or. one millimeter.

Referring' toLFigs. 1-an'dL2, aysourcel 0 of icarrier..microwaves. is connected'. to .inner conductor 1 I I- and outer. conductor.. I2, .botheof 4which constitute. a. coaxial. conductor .line .9.V .At the. left- ,.hand end of wave guide. .I 3,'.the outer conductor .12.- is electrically. connected thereto,- andra .por-

Idofthe.inner`.conductor II covered with .dielectric .I'I .extendsintotthe .,interior- `of Wave guides I3 .througha suitable opening. in .an upper sidewall. thereof. .The dielectricecovered portion I4 effects transmission between the coaxial line 4.9 andfwave guideI.3 inthe Well-known manner.

At the right-hand endof .wave-guide. I3, a similar coaxial line I&=eiects'.transmission betweenwave Vguide-I.3..and,load.19. IAfmicrowave transmission 4systemmi the foregoing .type .having `a suitable impedance. match ,Abetweenthe carrier source I0, wave guide..I3,.and"load..I-9is 'disclosed in the copending` application of W. W. MumfordSeria-l No.585.096,.-1edMarch 27, 1945.

"-Infaccordancewith the. present invention illustrated-.in Figs.. 1-and.2, opposite surfacesA 23 and '24 of wave fguidewlare constricted to provide therebetween a rectangular :opening 25 of univform dimensions, Eig. 5, andw-hose opposite ends terminate in ared-ropeningsrlf. Mounted .diagonally-off thesurface 23..-in suitable step-sis Aayplurality-.of rectier felements -28, .28 :whose specific function;andstructure-Will 4be hereinafter explained. Connected to Ieachv rectierelement .28l is Aone-end of :an electrical-lead- 29 whichextendslfacross the fopen-ing 25 `of wave .guide I3, projecting through -R.fF.:by-pass capacitorSIl .of -well-known structure.v fin surface 24 .I -and terminating at pointS Il lying outside -of wave guidey I3. The 1 leads 29, 29 -expose substantially -equal llengths in theopening 25. The rectifier Velements '28, 28 are-,shownrin the :number of.fve:for1the :purpose of .this illustration, .and such t number .may vary 'f or individualrmicrowavesystems.

IEach.' point I. isconnected via lead 32, secondary Windingof transformer 33, 'lead' 34.: and varia- .ble resistor `3 5. to the' negative terminal'of-.aisource 36:01 biasing'voltagehaving itspositive terminals grounded. AfsourcefSI of-.sgnalfwaves is connected-to the primarywinding offtransformer 33. Rectier .elementc28 vis shownwin 4Figsf ,and-4, and comprises a tubularemember 4 D of conductive material formed with a thread 4I on its interior surface, each member 49 being mounted in electrical contact with wave guide I3. At the uppermost end of tubular member 40 is a brass disk 42 provided with a peripheral thread and including a screwdriver slot 43 in its upper surface. Below the disk 42 and protected thereby from damage and/ or dust is a second disk 44 of conductive material formed with a peripheral thread to engage thread 4I of member 40, and a boss 45 on its lower surface. A disk 46 of a suitable semiconducting material is suitably secured to the lowermost surface of boss 45. Such material may include silicon or germanium or combinations 'of these elements with such other elements as tend to yield improved electrical properties. One method of preparing the disk 46 including a polished surface is disclosed in the copending application of R. S. Ohl, Serial No. 530,419, led April 10, 1944, now Patent No. 2,437,269. The disk 44 also embodies a screwdriver slot 43a.

A split ring 48 of tungsten wire is positioned on the polished surface 41 of the disk 46, and pressed thereon by a flat surface 49 on the upper end of a conductive cylinder 58 having a peripheral thread I and a screwdriver slot 52 in its lower end. A disk 55 of dielectric material embodies a central opening` 56 provided with a thread for accommodating the threaded peripheral surface of the cylinder 5D, and a peripheral thread for engaging the thread 4I of the member 46. A pair of screwdriver slots 51, 51 `is formed in the lower surface of the dielectric disk 55. Lead 29 is suitably attached tothe lower end of the cylinder 50. The screwdriver slots in the respective components of the rectifier element 28 serve to adjust their relative positions linteriorly of the member 49. For further details regarding the rectier element 28, reference is made tothe copending application of R. S. Ohl, Serial No. 607,427, filed July 27, 1945.

In the operation of the invention, the variable resistor 35 in Fig. 1 is adjusted and the source 36 is poled to apply a preselected magnitudevof negative biasing voltage to the split ring 4B. The :biasing current ows in a circuit comprising ground conected to the positive terminal of biasing source 36, source 36, resistor 35, lead l34,

secondary winding of transformer 33, lead 32,.

terminals 3|, leads 29, rectifier elements 28, 28 and wave guide I3 to ground B0 connected to the lower left-hand end thereof. The energy from signal source 31 is superimosed via transformer 33 on the biasing current flowing in the circuit just traced. The signal energy varies 4the effective resistivity of the combined elements 28, 28 and thereby the effective attenuation thereof. This varies the amount of carrier current absorbed by the rectifier elements 28, 28, and as a consequence the amount of carrier energy supplied to the load I9. Thus, the signal energy serves to modulate the carriery energy. v

Due to the diagonal disposition of the rectifier elements 28, 28 in suitable steps in the wave guide sections 23 and 24 and the equal lengths of the leads 29 in opening 25 in Fig. 2, the individual rectifier elements 28, 28 will absorb substantially the same amount of power. This tendstominimize reflections and thereby maintain the impedancematch between the carrier'source I0, wave guide I3 and load yI9 hereinbefore mentioned. The modulator comprising surfaces 23 and 24, opening 25 therebetween, flared openings, rectifier elements 28,l 28 and leads 29, 29 would be normally located inVproximity-'ofthe A 28, have been foundto pass 7.5 amperes at approximately one volt and to operate continuously at approximately degrees centigrade with no apparent impairment thereof. Thus, the recti er elements 28, 28 provide the microwave translating system with a substantially increased power handling capability.

' The lengths of the leads 29, 29 exposed in the opening 25 should not exceed one-quarter wavelength to provide 'the system of Fig. 1 with a broad-band characteristic. form a `frequency standpoint say, for example, several 'hundred megacycles at a Wavelength of the order lof one centimeter. The over-all spacing of the rectier elements 28, 28 should probably not exceedone Wavelength, nor be less than yone-half wavelength. 1 l Y Although the modulation is effected in Fig. 1 with a negative Ybia-s applied to the rectifier element 28, it will be understood that modulation can also be effected with a positive-bias applied to the rectifier element 28, inwhich case the terminals of the biasing source 36 are interchanged. 'Y

What is claimed is:

1. A microwave translating apparatus comprising, in combination, a section -of guide forthe transmission of microwaves, a plurality of .variable impedance elements, means for individually coupling said elements different distances from an antinodal region of maximumv eld intensity at respective succes-sive points along said section of guide, and electrical circuit means for varying the impedance of said elements concurrently. 1

2. A 'microwave translating apparatus according to claim 1 in whichsaid elements and coupling means are disposed along a straight line which is oblique to the longitudinal axis of said guide and which is on one side of such axis.

3. In combination, a section of guide for. the transmission of microwaves, and a plurality` of microwavepower absorbers individually coupled to the transmittedmicrowaves at respective successive points along said section of guide, the successive points being progressively closer to a region which with regard to the variation of field intensity transversely of said guide is -a region of maximum field intensity whereby such coupling of said absorbers progressively increases from one to another thereof.

4. A combination according .to claim 3 in which said power absorbers are coupled to absorb substantially Vequal amonnts of power from said mi` crowaves.

5.In combination, a section of guide for the transmission of microwaves and aY plurality of microwave power absorbersV individuallyV coupled to the transmitted microwaves at respective, successivepoints along saidv section of guide, the successive points being progressively closer to a regionv which with regard to the variation of eld intensity transversely of said guide Vis a region of maximum-field intensity wherebyv the coupling of said absorbers progressively increases from one to another thereof, and the successive points progressively approaching the center line of said section of guide.

6. In combination, a section of guide for the transmission of microwaves, a plurality of microwave power absorbers individually coupled to the transmitted microwaves at respective successive points along said section of guide, said absorbers comprising variable impedance elements, said successive points being progressively closer to a region which with regard to the variation of iield intensity transversely of said guide is a region of maximum field intensity whereby the coupling of said absorbers progressively increases from one to another thereof, said points progressively receding from a side wall of said section of guide, and electrical circuit means for varying the impedance of said elements concurrently.

'7. In combination, in microwave translating apparatus, a section of guide for the transmission of microwaves, a plurality of variable impedance elements mounted in said section of guide, said elements being so mounted in said section of guide that the respective elements lie different distances from the longitudinal axis thereof, a plurality of electrical leads for coupling said elements to the transmitted microwaves, each lead having one end connected to one of said elements and extending across the interior of said section of guide to project its opposite end outside thereof, said leads being exposed substantially the same amount in the interior of said guide, said mounting of said elements and leads associated therewith being at different distances from the longitudinal axis of said section of guide for varyingly coupling said elements to the transmitted microwaves, and electrical circuit means connected to the ends of said leads outside said section of guide for varying the impedance of said elements concurrently.

8. A combination a-ccording to claim 7 in which said elements are mounted diagonally of the longitudinal axis of said section of guide.

9. A combination according to claim 7 in which said section of guide has a substantially uniform cross-section.

10. A combination according to claim 7 in which said elements are mounted longitudinallyof said section of guide an over-all distance of at least one-half wavelength.

11. A combination according to claim 7 in which the amount of the exposure of said leads in the interior of said section of guide has a maximum value of the order of one-quarter wavelength.

12. A combination according to claim 7 in which said elements are mounted longtiudinally of said section of guide an over-all amount whose maximum value does not exceed one wavelength.

13. In combination, a section of Wave guide for the transmission of microwaves, and a plurality of variable impedance elements individually coupled to the transmitted microwaves at respective successive points along said section of guide, the successive points being progressively closer to a region which with regard to the variation of eld intensity transversely of said guide is a region of maximum field intensity.

14. In combination, a section of wave guide :for the transmission of microwaves, a plurality of variable impedance elements individually coupled to the transmitted microwaves at respective successive points along said section of guide, the successive points being progressively closer to a region which with regard to the variation of field intensity transversely of said guide is a region of maximum eld intensity whereby such coupling of said elements progressively increases from one to another thereof, and an electrical circuit external of said guide and interconnecting said plurality of elements.

DOUGLAS H. RING.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 2,047,930 Linder July 14, 1936 2,085,406 Zworykin June 29, 1937 2,106,770 Southworth et al. Feb. 1, 1938 

